In recent years, university, government, business, and financial service entities, among others, have increasingly relied upon data center networks that incorporate racks of server computers (“servers”) to implement application programs (“applications”) for supporting their specific operational requirements, including, but not limited to, data base management applications, document and file sharing applications, searching applications, gaming applications, and financial trading applications. As such, data center networks are generally expanding in terms of the number of servers incorporated therein, as well as the networking equipment needed to interconnect the servers for accommodating the data transfer requirements of the applications that the servers are called upon to implement.
Conventional data center networks typically have hierarchical architectures, in which each server co-located in a particular rack is connected via one or more Ethernet connections to a top-of-rack Ethernet switch (the “top-of-rack switch”). A plurality of such top-of-rack switches form what is generally referred to as the “access layer”, which is the lowest level of the hierarchical network architecture. The next higher level of the hierarchy is generally referred to as the “aggregation layer”, which can include a plurality of Ethernet switches and/or Internet protocol (IP) routers. Each top-of-rack switch in the access layer can be connected to one or more Ethernet switches and/or IP routers in the aggregation layer. The highest level of the hierarchy is generally referred to as the “core layer”, which includes a plurality of IP routers that can be configured to provide ingress/egress points for the data center network. Each Ethernet switch and/or IP router in the aggregation layer can be connected to one or more IP routers in the core layer, which, in turn, can be interconnected to one another. In such conventional data center networks, the interconnections between the racks of servers, the top-of-rack switches in the access layer, the Ethernet switches/IP routers in the aggregation layer, and the IP routers in the core layer, are typically implemented using point-to-point Ethernet links.
Although the conventional data center networks described above have been employed to satisfy the operational requirements of many university, government, business, and financial service entities, such conventional data center networks have drawbacks. For example, data communications between servers that are not co-located within the same rack may experience excessive delay (also referred to herein as “latency”) within the data center network, due in no small part to the multitude of switches and/or routers that the data may be required to traverse as it propagates up, down, and across the hierarchical architecture of the network. Data communications between such servers may also experience latency within the respective switches and/or routers of the data center network due to excessive node and/or link utilization. Further, because multiple paths may be employed to deliver broadcast and/or multicast data to different destinations within the data center network, such broadcast and/or multicast data may experience excessive latency skew. Such latency and/or latency skew may be exacerbated as the size of the data center network and/or its load increases. The hierarchical architecture of the data center network also generally suffers from increasingly complex but essentially fixed fiber cabling requirements, as the numbers of switches, routers, layers, and their interconnections are increased to handle the expansion of the data center network.
It would therefore be desirable to have data center network architectures, systems, and methods that avoid at least some of the drawbacks of the conventional data center networks described above.